Johns Hopkins U.S. bird flu infections have declined in both birds and mammals, prompting CDC to shift from weekly to monthly reporting. But is the outbreak really over? It’s not unusual for wild birds to be infected by influenza viruses.
But the strain of highly pathogenic avian influenza that began causing outbreaks in the U.S. in wild birds and on poultry farms in 2022 has had an unusual trajectory: It has infected humans and a range of other species from farm animals to marine mammals.
The U.S. has recorded only three cases of H5N1 in humans this year—compared with 67 in 2024. But that doesn’t mean we should lower our defenses, says Erin Sorrell, PhD, MSc, a senior scholar at the Center for Health Security and an associate professor in Environmental Health and Engineering. In a Q&A adapted from the July 21 episode of Public Health On Call, Sorrell explains why now is the time to prepare for migratory birds’ return to the U.S., and why we need an “integrated response” to H5N1 that connects data for all affected species.